HOUSING ▶▶▶


Impact of climate change on broiler housing systems


BY SAMANEH AZARPAJOUH B


y 2050 global meat consumption is expected to increase to 455 million tonnes per year in response to the expected population growth and dietary shift towards higher protein food. Broiler production is a


major part of the global meat market and the broiler industry is expected to meet approximately 40% of the increased universal demand for meat. Increasing and sustaining food production at this level will result in an increase in energy consumption. Conversely, there has been growing concern about the impact of climate change on broiler production given that it has been predicted that by the year 2100 the average temperature will increase by 2-6°C which constitutes a serious challenge to sustainable broiler production. Climate change will further influence the type and sophistication of broiler housing systems and alter the resource needs for broiler production. The economic and productive efficiencies of broilers are related to housing systems and climatic condi- tions. It is therefore essential to adapt broiler housing systems in line with the prevailing and envisaged climate change to minimise its adverse effects on the broiler industry.


Effects of climate change Climate change is defined as the long-term deviations in climate patterns and temperature. The increase in global tem- perature, along with the desert encroachment and deforest- ation associated with climate change, will add to the burden of heat stress experienced, especially in tropical regions and during summer. Heat stress promotes behavioural, physiolog- ical and biochemical changes in broilers, resulting in econom- ic losses. Additionally, it will lead to decreased water availa- bility and an increase in the cooling energy required thereby potentially compromising broiler production, reproduction, growth performance, health and welfare.


Controlling the microclimate Operating broiler houses at full capacity with bird flocks of uniform size is a common practice, one which enables more


Due to climate change, heat stress events are expected to become more frequent in broilers, with increased ambient temperatures adversely affecting broilers’ production, reproduction, growth performance, health and welfare. Reduced energy consumption for heating will be offset by increased energy use for cooling.


accurate control of the microclimate inside the barn and im- proves efficiency. Industrial broiler production involves con- trolling the indoor microclimate driven by the thermal flows occurring inside the broiler house and the requirements of the broilers throughout their growth stages. Heating, ventila- tion and air conditioning systems are used to control the temperature in the broiler house. In winter, mechanical venti- lation is used to circulate air and remove accumulated gases. In summer, ventilation and different forms of active cooling are used to maintain the inside temperature below a certain threshold. Evaporative cooling pads are the most common active cooling method used when temperatures exceed 30°C for periods of more than 2 to 3 hours.


Regulating body temperature Broilers have a limited capacity to respond to temperature alterations due to the absence of sweat glands. They can tolerate a narrow temperature range of 18°C to 24°C within their thermoneutral zone. In the thermoneutral zone broiler body temperature is held constant and the bird loses heat at a controlled rate without discomfort. Heat stress in broil- ers results in mortality or reduced weight gain, decreased production, diminished reproduction and reduced growth performance, together with compromised welfare. When the ambient temperature is high, broilers need to regulate their body temperature through panting, resting, drinking water and reducing physical activity to balance heat pro- duction against heat loss and maintain a relatively constant body temperature.


▶ POULTRY WORLD | No. 2, 2022 11


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36